People gather at Quicken Loans Arena as preparations take place for the Republican National Convention, Sunday, July 17, 2016, in Cleveland. Photo Credit: AP / John Locher

CLEVELAND — Republican delegates have converged on this Rust Belt city for the weeklong national party convention that kicks off Monday and is expected to make official the nomination of Donald Trump for president.

National security, defense and safety are the theme Monday for both the national stage at the Quicken Loans Arena and the breakfast hosted by the New York State GOP at the Renaissance Cleveland Hotel.

According to a program released Sunday evening, headliners at the convention center include Trump’s wife, Melania, a businesswoman and former model; retired U.S. Army Lt. Gen. Michael Flynn, former director of the U.S. Defense Intelligence Agency; and Sen. Joni Ernst (R-Iowa).

Former New York City Mayor Rudy Giuliani, former Texas Gov. Rick Perry, “Duck Dynasty” reality TV star Willie Robertson and Scott Baio, an actor who appeared in the 1980s TV series “Charles in Charge,” are also among the speakers.

The GOP said in a news release that the foreign policy and open-border immigration approach of President Barack Obama and former Secretary of State Hillary Clinton, the presumptive Democratic presidential nominee, have “left us vulnerable.”

“What happened in Orlando, what happened in San Bernardino, what happened in Nice, what happened in Paris . . . shows that ISIS, while they’re losing territory, in some ways they’re more lethal than ever,” Rep. Peter King (R-Seaford) told Newsday at the state delegates’ hotel. “So how do we deal with the evolving ISIS? They’ve metastasized, they can adapt.”

The state GOP will host a breakfast panel at the Renaissance also focused on national security and defense.

The discussion will be led by former House Speaker Newt Gingrich, who was a finalist for Trump’s vice president; Sen. Bob Corker (R-Tenn.); and conservative commenter Larry Kudlow.

Cox told Newsday that the terrorist attack that killed 84 in Nice, France, last week pointed to a looming threat to the United States.

“We know they’re going to come here,” he said of terrorists, also blaming the policies of Obama. “To keep a peaceful world, you need to have a strong American leadership out there, and when you show weakness that’s when you end up having wars.”

This week’s events in Cleveland, which are expected to culminate in an acceptance speech Thursday night by Trump, must serve to unify the factions of the Republican Party behind the Manhattan real estate mogul and his newly announced running mate, Indiana Gov. Mike Pence, experts said.

State Senate Majority Leader John Flanagan (R-East Northport) said in an interview that he expects the party will come together behind Trump, because the candidate has earned the nomination.

“He has been in the milieu, the mosh pit, the peaks and valleys for 18 months and the reality is, he’s still standing because he has tapped a nerve and listened to people,” Flanagan said. “I think that is important.”

With Michael Gormley

Monday’s schedule at the Republican National Convention in Cleveland, Ohio.